532 PRANK R. LILLTE 



that the escape of nuclear sap furnishes the necessary conditions. 

 In some eggs, therefore* we might anticipate that sufficient sub- 

 stance might exude from the germinal vesicle without rupture to 

 bring about formation of active fertilizin. Theoretically this 

 should occur in such eggs as those of Nereis in which fertilization 

 occurs before rupture of the germinal vesicle. 



c. Fertilizin produced in a series of washings; role of the jelly 



The production of this substance by the egg, in sea-water must 

 be regarded as an active process of secretion, and, as will be seen 

 immediately, it goes on continuously, in the case of Arbacia, as 

 long as the eggs remain alive. 



The last fact was ascertained in several attempts to remove all 

 the fertihzin from the eggs by repeated washings. In these 

 experiments it was also ascertained that while the jelly layer 

 surrounding the eggs is saturated with fertilizin, eggs deprived of 

 jelly still continue to produce it in considerable quantities. The 

 method of making such tests is to suspend a measured amount of 

 eggs in a given amount of sea-water and allow them to settle; 

 as much of the supernatant fluid is then poured off as is possible 

 without losing any eggs and kept for testing, and an equivalent 

 amount of fresh sea- water replaced; the eggs are mixed up 

 thoroughly, and allowed to settle, and the process is continued. 

 In one series running three days in which the quantity of eggs 

 was originally 2 cc. and the total volume of sea-water and eggs 

 in the tube 10 cc, 6 to 8 cc. being poured off at each settling, 

 thirty-four changes were made, and the agglutinating strength 

 of the supernatant fluid diminished from 100 at first to 20 at the 

 end. The details are given in table 2: Under the heading 

 'washings' the denominator gives the quantity of eggs and sea-water 

 left after pouring off the supernatant fluid, and the numerator 

 the total quantity after addition of the fresh sea-water. 



This long series is amazing in its revelation of the extraordinary 

 energy of the eggs in producing the fertilizin. In this case the 

 eggs were allowed to retain their jelly, which, however, slowly 

 dissolved until it was nearly all gone in washing 24. 



